---
title: "Browser Support & Polyfills"
description: "Note on browser support in ReScript"
canonical: "/docs/manual/browser-support-polyfills"
section: "JavaScript Interop"
order: 13
---

# Browser Support & Polyfills

ReScript compiles to JavaScript **ES5**, with the exception of optionally allowing to compile to ES6's module import & export.

For [old browsers](https://caniuse.com/#search=typed%20array), you also need to polyfill TypedArray. The following standard library functions require it:

- `Int64.float_of_bits`
- `Int64.bits_of_float`
- `Int32.float_of_bits`
- `Int32.bits_of_float`

If you don't use these functions, you're fine. Otherwise, it'll be a runtime failure.
